
\begin{tikzpicture}[scale=.35]
  \tkzDefPoints{0/0/O_1,3/0/O_2,8/0/S}
  \tkzDefPoint(60:8){A}
  \tkzDefLine[tangent from=A](O_2,S)
    \tkzGetSecondPoint{C}
  \tkzInterLC(A,C)(O_1,S)  \tkzGetSecondPoint{B}
  \tkzDefLine(A,B)          \tkzGetPoints{m1}{m2}
  \tkzInterLC(m1,m2)(O_1,S) \tkzGetFirstPoint{M}
  \tkzDefMidPoint(A,B)      \tkzGetPoint{N}
  \tkzDrawCircles(O_1,S O_2,S)
  \tkzDrawSegments(A,B M,N)
  \tkzMarkRightAngle[size=.5](M,N,B)
  \tkzDrawPoints(A,B,C,S,M,N)
  \tkzLabelPoints(B,N)
  \tkzLabelPoints[right](S)
  \tkzLabelPoints[left](M)
  \tkzLabelPoints[above](A,C)
\end{tikzpicture}
